Method of producing bars or sections by continuous casting



Oct. 5, 1965 E. SCHNECKENBURGER 3,209,452

METHOD OF PRODUCING BARS OR SECTIONS BY CONTINUOUS CASTING Filed May 2,1962 2 Sheets-Sheet 1 dlllll II/ at l/lII/l/I United States Patent3,209,452 METHOD OF PRODUCING BARS 0R SECTIONS BY CONTINUOUS CASTINGEmil Schneckenburger, Emmenbrucke, Switzerland, assignor toAktiengesellschaft der von Moosschen Eisenwerke, Ernrnenbrucke, Lucerne,Switzerland Filed May 2, 1962, Ser. No. 191,850 Claims priority,application Germany, May 5, 1961, A 37,366 7 Claims. (Cl. 29-528) Thisinvention relates to a method of producing bars and sections bycontinuous casting. The conventional method of producing bars andsections by continuous casting consists in casting each bar separatelyin a continuous casting mould and in then cutting the bar at appropriateintervals to provide the required lengths. It has also been proposed toproduce several bars simultaneously in one machine in one mould. Thismethod is known as the multiple mould continuous casting technique.

If it is desired to produce sections, then either the bars may be rolleddown to the required sections or each section may be continuously castindependently of the other, but in practice this gives rise toconsiderable difiiculties. Particularly in multiple mould continuouscasting machines trouble often arises because it is diflicult tomaintain exactly similar conditions in each continuous casting.

One difiiculty which arises in multiple mould continuous castingmachines is that of ensuring a satisfactory distribution of the melt. Inorder to prevent the melt from solidifying in the distributor and alsoto avoid absorption of oxygen it is usually the aim to feed the meltinto the mould along the shortest possible path. This means that theseveral castings must be withdrawn from the mould in closely adjacentjuxtaposition. Difiiculties then arise in locating the withdrawingmeans. It is impossible to provide separate withdrawing means for eachcontinuous casting. It had thus been proposed to provide driving rollerof adequate length to withdraw several castings simultaneously side byside. However, it has been found that diiferential wear of the drivingrollers impairs contact between rollers and metal and that this leads toirregular withdrawal of the several castings. Subsequent readjustment ofthe rollers is impossible if there are three or more castings so thatthis proposal is not generally used in machines delivering more than twocastings.

The object envisaged by the present invention is the simultaneousproduction of several bars by continuous casting without incurring thetroubles due to the difiiculty of uniformly feeding the metal into themultiple mould and of withdrawing the several castings from the mould.The invention also proposes to provide the means for producing sectionsby a particularly convenient and advantageous method of manufacturewithout the necessity of first producing a bar as an intermediateproduct.

To this end the invention consists in first producing rectangular orsubstantially rectangular flat or grooved slabs by continuous castingand in then further deforming the slabs in continuous operation,dividing them into a plurality of continuous sections or bars.Deformation and division into several bars or sections is preferablydone by rolling the slabs between grooved rolls.

Preferably therolled material may be elongated Without spreading bybeing rolled down in grooved rolls forming closed passes.

In order to overcome the difiiculties which arise when feeding theleading end of the continuous casting into the rolls it is preferred notto set the rolls and not to close the passes until the leading end ofthe casting has been gripped by the rolls. The diameter of the rollsneed not then be excessively large.

The proposed method permits finished bars or sections to be produced inonly one or only a few passes. Conventional methods of rolling wouldrequire a fairly large number of passes.

If the necessary deformation cannot be achieved with a single pair ofrolls, rolling may be in stages in several consecutive roll stands eachfitted with rolls having progressively sharper ridges between thegrooves.

The rolled material issuing from the shaping rolling mill or from thefinal roll stand may be divided into completely separate bars orsections by conventional cutting means, such as cutting rolls, circularshears, reciprocating shears, cutting discs, brake cutting devices orbreaking machines, the bars or sections still being connected togetherby a fairly thick flash when they issue from the final pair of groovedshaping rolls.

The invention also relates to special contrivances and apparatus forperforming the method according to the invention.

The invention will now be more particularly described by reference tothe accompanying drawings.

In the drawings:

FIG. 1 schematically illustrates a continuous casting plant comprising apermanent mould for producing a grooved continuous casting, a guidewaywhich for the sake of simplicity is shown as consisting of cylindricalrollers and at the end of the guideway a pair of grooved rolls;

FIG. 2 illustrates a pair of grooved rolls for rolling bars, seen in thedirection of rolling;

FIG. 3 similarly shows a pair of rolls for rolling angle sections; and

FIG. 4 illustrates the use of a grooved backing roll.

A conventional metal feeding means is indicated at 1. In the illustratedembodiment this is assumed to be an ordinary teeming ladle which chargesthe liquid metal into a shaped permanent continuous casting mould. Acontinuous casting 3a which already possesses a solidified outer skinemerges from the mould 2 and is further guided between rollers 4 whichgradually turn the casting from the vertical into the horizontaldirection. All the rollers 4 are driven by a common drive means notspecially shown in the drawing. Endwise location of the continuouscasting 3a is effected by lateral guide rollers 5. 6 are sprayingnozzles which spray a coolant on to the continuous metal casting 3a andon to the guide rollers 4. After having passed through a rollerstraightening machine the continuous casting passes through several setsof grooved rolls of which only one pair 7 is shown in the drawing.

The illustrated plant functions as follows:

The continuous casting 3a which already possesses a solidified skin asit issues from the permanent mould 2 is guided between the driven guiderollers 4 which gently turn the casting into the horizontal direction.The coolant sprayed from the nozzles 6 causes the casting 3a which isdeeply grooved because of the particular shape of the mould, to solidifycompletely. Having travelled through a straightening machine not shownin the drawing the continuous casting 3a passes through one or morepairs of grooved rolls, the final set of grooved rolls having a cuttingaction and longitudinally separating the deeply grooved continuouscasting into adjacent separate bars which are finally cut to suitablelengths by a cross cutting device,

The straightening machine may of course be located at some other pointthan that specified in the foregoing description.

Alternatively, the longitudinal division of the deeply groovedcontinuous casting may be effected by cutting means of some other knownkind, such as circular cutting sears, reciprocating shears, oxyacetylenecutters or breaking machines which then take the place of the cuttingrolls.

It is also within the scope of the present invention to replace thegrooved permanent mould which produces a preshaped continuous casting bya mould of conventional rectangular section, the narrow sides having anydesired conformation, for instance a circular shape. A continuouscasting which is not already grooved may be divided in various ways, forinstance by grooving the casting by a pass through grooved rollsfollowed by cutting rolls or by any of the above mentioned cuttingdevices to effect the final longitudinal separation of the casting intoseveral bars, or the continuous cast slab may be divided by knowncutting means including oxyacetylene cutting without previous rolling.Moreover, the continuous casting, irrespectively as to whether this hasbeen preshaped in the mould or whether it issues from the mould as aflat slab need not be turned from the vertical into the horizontalbefore division takes place. The rolling of the divided slab can thenproceed at a higher rate.

FIG. 2 illustrates a grooved pair of rolls for rolling wire bars ofsection 10. The bottom roll 11 has flanges 12 which embrace the sides ofthe upper roll 13. The openings or passes are closed so that the rolledmaterial cannot spread sideways. The prevention of lateral spread iseven more effectively achieved between rolls shaped as shown in FIG. 3,where the flange 12a of the bottom roll 11 directly defines the outsidepass 14 for the production of a plurality of angle sections. The slabfrom which four angle sections 15 are rolled enters between the twoflanges 12a and is therefore prevented from laterally spreading. Onlyelongational deformation is possible. The faces 16 of the flanges 12acontacting the sides of the top roll 17 completely close the passes 14.

Since the necessary roll pressure is rather high the provision ofbacking rolls may be advisable. This is further illustrated in FIG. 4where a working roll 21 with grooves 22 is supported by a backing roll23. The backing roll 23 bears only on the faces marked 24 of the workingroll. These are faces which are not subjected to the severest stresseswhen rolling. The ridges 25 between the grooves of roll 21 are notexposed to the backing pressure because they freely project intorecesses 24 in the backing roll.

What I claim:

1. A method of producing bars and sections by continuous casting, saidmethod comprising the steps of feeding molten metal into a moldcomprising a mold chamber having an input end, freezing zone andwithdrawing end, said ends having slab-like and slightly indented crosssection, withdrawing a strand from this mold, guiding said strandissuing from said mold in a desired path, cooling the strand in saidpath to complete solidification and to provide a desired hot-workingtemperature, straightening said strand, guiding the leading end of thestrand between spaced grooved rolls, closing and setting said rolls andhot-working said strand in continuous operation to divide said strandinto a plurality of laterally adjacent bars or sections of desired crosssection.

2. Apparatus for producing bars and sections by continuous casting, saidapparatus comprising a cooled flowthrough mold of substantially constantand slightly indented cross section, said cross section being such as toform a cast strand of slab-like cross section provided with shallowlongitudinal indentations, a plurality of guide rollers defining adesired path beginning adjacent to said mold for guiding said strandissuing from said mold along said path, a plurality of coolant sprayingmeans associated with said rollers and directed toward said path forspraying a cooling fluid on said strand, means for straightening saidstrand, at least one roll stand, at least one roll of said roll standbeing formed with circumferential grooves corresponding in number andposition to the indented parts of said mold cross section forhot-working the strand into bars and sections.

3. Apparatus for producing bars and sections by continuous casting, saidapparatus comprising a cooled flowthrough mold of substantially constantand slightly intended cross section, said cross section being such as toform a cast strand of slab-like cross section provided with shallowlongitudinal indentations, a plurality of guide rollers defining adesired path beginning adjacent to said mold for guiding said strandissuing from said mold along said path, a plurality of coolant sprayingmeans associated with said rollers and directed towards said path forspraying a cooling fluid on said strand, means for straightening saidstrand, a plurality of roll stands in said path of said strand, eachstand having a pair of cooperating grooved rolls, which define alaterally closed pass, each successive pass being more constricted andhaving sharper projections, for hot-working the strand into bars andsections.

4. Apparatus for producing bars and sections by continuous casting, saidapparatus comprising a cooled flowthrough mold of substantially constantcross section, said cross section being such as to form a cast strand ofslablike cross section provided with shallow longitudinal indentations,a plurality of driven guide rollers defining a desired path beginningadjacent to said mold for guiding said strand issuing from said moldalong said path, a plurality of coolant spraying means associated withsaid rollers and directed toward said path for spraying a cooling fluidon said strand and rollers, a plurality of roll stands in the path ofthe strand, each stand having a pair of cooperating rolls of which atleast one is formed with circumferential projections corresponding innumber and position to said indentations, each stand defining alaterally closed pass, each successive pass being more constricted andhaving sharper projections, whereby said strand will be formed into aplurality of laterally adjacent bars or sections of desired crosssection and means for straightening said strand.

5. Apparatus according to claim 4, wherein said mold is substantiallyvertical and said path is a curve extending from said mold and having asubstantially horizontal termination, said straightening means beingdisposed adjacent to said termination and preceding said roll stands.

6. Apparatus according to claim 4, wherein one roll of a stand hasradial end flanges embracing the ends of the co-operating roll, andwherein each roll is backed by a grooved backing roll bearing only onparts of the roll that are not highly stressed during rolling.

7. Apparatus for producing bars and sections by continuous casting,comprising a cooled flow-through mold of substantially constant andslightly indented cross section, said cross section being such as toform a cast strand of slab-like cross section, provided with a shallowlongitudinal indentation, a plurality of guide rollers defining adesired path beginning adjacent to said mold for guiding said strandissuing from said mold along said path, a plurality of coolant sprayingmeans associated with said rollers and directed toward said path forspraying a cooling fluid on said strand, means for straightening saidstrand, a plurality of roll stands in said path of said strand, eachstand having a pair of cooperating grooved rolls which define alaterally closed pass, each successive pass being more constricted andhaving sharper projections,

5 6 whereby said strand will be hot-worked into a plurality 2,711,5776/55 Leach 29-528 X of laterally adjacent bars or sections of desiredcross sec- 2,947,025 8/60 Schneckenburger et a1. 29-528 X tion andcutting means succeeding said stands for longi- 2,975,493 3/61 Morton eta1. 22-572 X tudinally separating said bars or sections. 3,147,521 9/64Boehm 29-528 X References Cited by the Examiner 5 OTHER REFERENCESUNITED STATES PATENTS Making, Shaping and Treating of Steel, U.S. SteelG eer C(L, 2 3331232 9??? 33 5;525:2211:ij'iilifif 10 WHITMORE WILTZPrimary 2,053,375 9/36 Nichglas, JOHN F. CAMPBELL, Examiner.

1. A METHOD OF PRODUCING BARS AND SECTIONS BY CONTINUOUS CASTING, SAIDMETHOD COMPRISING THE STEPS OF FEEDING MOLTEN METAL INTO A MOLDCOMPRISING A MOLD CHAMBER HAVING AN INPUT END, FREEZING ZONE ANDWITHDRAWING END, SAID ENDS HAVING SLAB-LIKE AND SLIGHTLY INDENTED CROSSSECTION, WITHDRAWING A STRAND FROM THIS MOLD, GUIDING SAID STRANDISSUING FROM SAID MOLD IN A DESIRED PATH, COOLING THE STRAND IN SAIDPATH TO COMPLETE SOLIDIFICATION AND TO PROVIDE A DESIRED HOT-WORKINGTEMPERATURE, STRAIGHTENING SAID STRAND, GUIDING THE LEADING END OF THESTRAND BETWEEN SPACED GROOVED ROLLS, CLOSING AND SETTING SAID ROLLS ANDHOT-WORKING SAID STRAND IN CONTINUOUS OPERATING TO DIVIDE SAID STRANDINTO A PLURALITY OF LATERALLY ADJACENT BARS OR SECTIONS OF DESIRED CROSSSECTION.